15This meta-analysis shed light on the quantitative adaptive responses of feeding 16 behaviour of Cattle (C) and Small Ruminants (SR), facing variations of sward 17 characteristics, notably of sward height (SH, 18. 7 13.9 cm) and herbage bulk density 18 (HBD, 1.73 1.30 kg DM / m 3 ). All responses expressed a plateau stressing an 19 adaptive limit with extreme values of SH and HBD. The minimum plateau of BR (46.9 20 14.6 min-1) is around 40 min-1, while IR values (different for C and SR , respectively 21 69.1 38.1 vs. 99.9 45.7 g/min/kg BW) ranged between a minimum and maximum 22 plateau around 50 and 100 g/min/kg BW. Two other pasture management factors affect 23 IR, namely forage allowance (10.16 6.0, DM % BW) and daily proportion of time 24 spent grazing (0.30 0.08). The results obtained confirm the specifically key role of 25 2 BM (1.80 127 mg DM/kg BW) on IR. The regressions are IR=145 (1-exp (-b BM), b 26 being equal respectively for C and SR and C to 0.44 vs. 0.54. This literature review 27has also revealed fundamental differences in behaviour between C and SR although 28 no study to date has attempted to compare them simultaneously. SR have to chew 29 more (2.7 1.2 vs. 1.6 0.5 JM/bite) to ingest the same amount of DM per bite than 30 C, expressed in relation to BW, which allow them to ingest slightly quickly. 31 32 Keywords (5): Intake rate, Bite Rate, Sward height, Herbage bulk density 33 34 Implications 35 This article, following the previous one of Boval and Sauvant (2019), proposes a 36 quantitative appraisal of the ingestive behaviour of grazing ruminants, based on 37 studies published over 40 years, as well as well robust average values and 38 relationships, considering inter-and intra-study effects and animal species 39 specificities. This knowledge should contribute to a better overall understanding of the 40 behavioural adaptation of ruminants at pasture, to the identification of key threshold 41 values and appropriate parameters of interest to be considered, and to improve the 42 efficiency and sensitivity of automatic devices, which are booming in the context of 43 precision livestock farming at pasture. 44 45 48feeding context. Ingestive behaviour determines the nutrient supply to ruminants and 49 thus has a significant impact on performance and feed efficiency, which are essential 50 3 for increasing the profitability of livestock (Llonch et al., 2018; Shalloo et al., 2018). 51 Moreover, a ruminant's robustness partly comes from its ability to adapt IB to the 52 diversity of resources to be grazed. In addition, chewing behaviour provides 53 information about digestive comfort and indicators of appetite, gut health and welfare. 54 Numerous studies have focused on the IB of grazing ruminants. However, beyond the 55 problems linked with the diversity of the methodologies applied, the items measured 56 are very heterogeneous across publications. Likely for this reason, no synthetic 57 statistical interpretation of published IB data for ruminant grazing has been ...
